Organic Light-Emitting Diode (OLED) display panels are favored by people because of having characteristics such as thin, power saving, wide viewing angle, wide color gamut, high contrast, etc. The OLED display panels are divided into Passive Matrix OLED display panels (PMOLED) and Active Matrix OLED display panels (AMOLED). The OLED driving circuit generally used in the AMOLED are shown in FIG. 1. The OLED driving circuit is used for driving the OLED and comprises a switch thin film transistor (switch TFT) T2, a driver TFT T1 and a storage capacitor Cst, which is also referred to as a 2T1C structure. The gate of the switch TFT T2 receives an nth scan signal Scan(n), the drain of the switch TFT T2 receives data voltage Vdata, and the source of the switch TFT T2 is electrically connected to the gate of the driver TFT T1. The transmission path between the source of the switch TFT T2 and the drain of the switch TFT T2 is turned on or off under control of the nth scan signal Scan(n). When the transmission path between the source of the switch TFT T2 and the drain of the switch TFT T2 is turned on under control of the nth scan signal Scan(n), the data voltage Vdata is transmitted to the gate of the driver TFT T1. The source of the driver TFT T1 is electrically connected to a source voltage VDD, the source voltage VDD is a high potential voltage, and the drain of the driver TFT T1 is electrically connected to the positive electrode of the OLED. The negative electrode of the OLED is electrically connected to a low potential voltage VSS. The two terminals of the storage capacitor Cst are electrically connected to the gate of the driver TFT T1 and the drain of the driver TFT T1, respectively. The current IOLED flows through the OLED is:IOLED=k(Vgs−Vth)2 
Wherein, IOLED is the current flow through the OLED and also referred to as the driving current of the OLED; k is a current amplifying coefficient of the driver TFT T1 and determined by the characteristics of the driver TFT T1; Vgs is the voltage between the gate and the source of the driver TFT T1; Vth is the threshold voltage of the driver TFT T1. It can be understood that the driving current of the OLED is related to the threshold voltage Vth of the driver TFT T1. Because the threshold Vth of the driver TFT T1 is easily shifted, the driving current IOLED of the OLED varies accordingly. The variation of the driving current IOLED of the OLED results in variation of luminance of the OLED, and the display quality of the AMOLED display panel is affected accordingly. Furthermore, voltage drop of the source voltage VDD occurs because of long-distance transmission. Therefore, the driving current IOLED flow through the OLED is varied, which is called as IR drop, and the illuminance of the OLED is varied and the display quality of the OLED display panel is affected, too.